Cruden is only one of the XV but he is the new engine in the machine and if he falters or has a stuttering impact because the forwards have not done their business, the All Blacks will stutter. That is reality. If he is fluent and decisive, then the All Blacks' prospects are stronger.
Right now, Cruden is as relaxed as a 22-year-old with seven tests experience could be. He knows the nerves will arrive.
"They will come and that is natural. I want to try and stay relaxed and focused," he said. "Against Australia it is always an epic battle and chuck a semifinal into the mix and it is huge."
Cruden's game has moved on from Sydney last year where he was nervous and put extra pressure on himself to produce a high quality game.
"This time the boys said go out there and play your natural game."
If the Wallabies want to target him, bring it on, he is ready.
One of the Wallabies wavering between almost and maybe is fullback Kurtley Beale. He will need to pass a fitness test today to be in the side.
Both teams announced yesterday were predictable combinations, although Victor Vito and Rob Simmons were different calls in the reserves.
The All Black pack has a familiar look, it has been groomed for some time but the backs are a new collection. Israel Dagg, Cory Jane and Richard Kahui are an apprentice combination in the back three, Cruden is a rookie and Piri Weepu has subbed more than started at halfback.
Like twitter accounts, skateboarding has been banned from the All Black repertoire until after the World Cup.
Coach Graham Henry acknowledged the lift in pressure for Cruden. He has gone from a substitute against Argentina to the man in charge of driving the All Black machine.
"But he is a bright rugby player, he knows the game well, he has captained a lot of teams he has been in," the coach said.
"He directs the traffic well but it is a big game, the biggest game he has played in and the biggest game a lot of them have played in, quite frankly. I'm sure it is challenging but he is handling it well."
Cruden would be a very good footballer. Henry stopped himself as though he was wondering when. Then he continued. Cruden was learning fast, he was wiser and sounder in his play than last season.
There had been selection ructions caused by injury and form changes but Henry said they had been together for a while and there would be no excuses if tomorrow ended in tears.
Across town at the Wallaby headquarters there will be uncertainty about Quade Cooper. He has not yet fired in this tournament. They need him tomorrow even more than the All Blacks need Cruden to be constructive.
If Cooper gets enough possession and stings as he can, the defensive system of the All Blacks will be under seige. They need captain Richie McCaw and Kieran Read in harmony to assist Jerome Kaino and repel the Wallabies.
But injuries deliver uncertainty. McCaw has rested all week to give his damaged foot some respite and his will is as menacing as anyone who plays test rugby. It will need to be to quell a thriving David Pocock in the last and most intriguing transtasman stoush this year.